Review: Edelrid Spoc

The Petzl Micro Traxion finally has some competition in the form of the new Edelrid Spoc! Given the popularity of the incredibly useful device, I’m surprised it took so long for a competitor to one-up Petzl. A testament to how well the unit was designed really. And Edelrid didn’t just copy the Micro Traxion, they made a few improvements as the Spoc is lighter, more efficient and less expensive. What more could you ask for? That being said, it’s not all sunshine and rainbows. The Spoc has a few quirks which are explored in more detail below.

Spec Comparison: Spoc vs. Micro Traxion

	Edelrid Spoc	Petzl Micro Traxion
Weight	61g	80g
Pulley Diameter	20mm	27mm
Efficiency	92%	91%
Min Rope Diameter*	7mm	8mm
Max Rope Diameter	11mm	11mm
Max Capacity	15kN	15kN
Max Progress Capture Load**	4kN	4kN
Cost***	$120	$175

Construction:

The Spoc is made from two aluminum housing plates that sandwich a pulley made of aluminum bearings and sheave. The spring-loaded toothed cam is made of steel while the top spacer which houses the cam lock-out is made of plastic.

The Basics: Spoc Design and Use

The new Spoc is an ultralight directional pulley, very similar to the Micro Traxion in basic design. It features a high quality pulley with a retractable toothed cam. The cam is designed to allow the rope to easily and efficiently travel through the device in one direction but not the other. Of course this makes it great for use as a progress capture device in crevasse rescue scenarios, an efficient single-strand rope ascender or rope grab and of course great for hauling when you don’t want to climb with a pack. The directional cam can also be retracted and locked out making it a great pulley.

Functionality:

The Spoc’s lock-out for the progress capture cam is a thin cord that’s cinched into a tapered wedge.

As we mentioned above, the cam on the Spoc can be retracted and locked out in a similar-but subtly improved-fashion compared to the Micro Traxion. The big issue with the small lock-out on the Micro Traxion is the ease with which it comes unlocked. Just bump the unit and it seems to fall back into progress capture mode! The Spoc on the other hand uses a small polyester cord that can be used to both retract the toothed cam and secure it in place. The lock itself is a ribbed constriction that cinches on to the synthetic cord. A very simple and elegant design. The cord does not seem to be replaceable without a lot of effort which could make it a weak point if abused (burnt, cut, etc.). The only downside to this cord lock-out system is the potential for accidental use that would defeat the progress capture given the large rubberized end on the cord. Not the end of the world, just something to be aware of when using the device.

The arrow on the inside of the Spoc points in the direction the rope will NOT move… a strange choice.

When loading a rope into the Spoc the side plate is slid open and the rope laid over the pulley. Simple, right! Well, yes and no. The rope has to be loaded such that the progress capture is set on the correct side to allow the load to be pulled up but not fall back down. To help people load the rope correctly Edelrid put an arrow on the inside of the device showing which way to load the rope. However, for some strange reason the arrow points in the direction that the cam will stop the rope. Put another way, the arrow points in the direction NOT to load the rope. A bit confusing so I plan to use a sharpie to fix it.

Spoc Rope Compatibility:

As with most devices that grab the outside of a rope, the strength of the Spoc’s progress capture cam is really dictated by the strength of the sheath of a given rope. Pull hard enough and the cam will strip the sheath off the rope. This is true of the Micro Traxion, Tibloc, Ropeman, etc. Even prusik hitches slip and can damage a rope, albeit less catastrophically. Climbing ropes are designed such that the sheath will not fail until at least 4kN, as are specialty rescue ropes such as the RAD Line. The Spoc is compatible with any climbing rope down to minimum diameter of 7mm. However, it will also be compatible with thinner cords (not technically climbing ropes as they undergo a different certification process) so long as the sheath has been designed and tested for that type of service. With that in mind I’ve commented on the compatibility of the Spoc with some of the more common thin specialty ropes currently on the market below.

A selection of thin ropes that could potentially be used with the SPOC. From left to right: Mammut Glacier Line (6mm), Beal Back Up Line (5mm), Petzl RAD line (6mm), Edelrid Rap Line II (6mm), Sterling Trace Rope (6mm) and Edelrid Skimmer Half/Twin Rope (7.1mm).

Thin Rope Compatibility:

Petzl RAD Line (6mm): Not specifically tested for use with the Spoc. However, I expect that it would work fine as the sheath on the RAD line was designed to be used with the Micro Traxion and so has the requisite sheath strength.
Mammut Glacier Rope (6mm): Again, not specifically tested for use with the Spoc (yet) though I suspect it would also work fine.
Edelrid Rap Line II (6mm): Yes, compatible with the Spoc
Beal BackUp Line(5mm): Beal has designed some rope grabs that work with this 5mm string specifically for glacier rescue but I personally think I’d like to see a bit more info before committing myself over the lip of a crevasse.

Head-to-Head Comparison to the Micro Traxion:

The Spoc is functionally identical to the Micro Traxion but lighter and less expensive. A pretty easy call. The only real downside is the backwards loading arrow, but that’s easy to fix.